<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<div id="app">
    <h1 v-if="ok==='A'">A</h1>
    <h1 v-else-if="ok==='B'">B</h1>
    <h1 v-else>其他</h1>
</div>

<script src="https://cdn.jsdelivr.net/npm/vue"></script>
<script type="text/javascript">
    var vm = new Vue({
        el: "#app",
        data:{
            ok:"A"
        }
    })
</script>
</body>
</html>